The present invention relates to base stations and base-station control apparatuses, and more particularly, to a base station and a base-station control apparatus for performing packet priority control in a packet communication system that handles a plurality of subscribers.
In addition to conventional wired communication networks, wireless communication networks (hereinafter called wireless communication systems) that use wireless terminals and a wireless communication apparatus have been introduced. In the wireless communication systems, code division multiple access (CDMA) communications, which code-multiplexes signals, such as audio signals, with spreading code to perform communications have been widespread as well as time division multiple access (TDMA) communications, which time-division multiplexes signals, such as audio signals, to perform communications. The CDMA method provides easier connection establishment and less disconnection, and also has a better sound quality than a personal digital cellular (PDC) method. In addition, since the CDMA method uses spectrum spreading in a wide band, it is immune to interference waves and noise.
The packet communication speed has been increased by cdmaOne, which is a communication method using the CDMA technology, and cdma2000, which is an upper standard of the cdmaOne. Especially in cdma2000 1×EV-DO, which is a data communication standard included in cdma2000, a maximum downstream data rate of 2.4 Mbps has been implemented.
In the wireless communication systems, a base station, serving as a wireless communication apparatus, communicates with a wireless terminal in an area where radio waves sent from the base station reach, which is called a cell. Generally, the cell has a radius of about several kilometers. About 200 users, for example, can perform communications in the cell. The wireless communication apparatus and another communication apparatus communicate with each other by successively handling packet data sent to and received from the users.
When a plurality of users send a large amount of packet data to impose heavy traffic on the line, if a user wants to make a new connection to a service, the connection is not established soon in some cases. Alternately, even when that connection is established, no response is sent back soon from an application program of the destination. To eliminate a sense of unfairness perceived by the users where a later attempt to make a connection is more likely to fail, it is demanded that a delay of a new-connection packet be eliminated.
Currently, the quality of service (QoS), which ensures a packet frequency band, is provided as a technology for guaranteeing that the users can use constant-rate transmission and reception. Irrespective of whether the QoS is provided or not, a technology for providing the users with a uniform service is also disclosed (for example, in Japanese Unexamined Patent Application Publication No. Hei-08-191328).
In that technology, a priority level is assigned to each of a plurality of packet communication terminals, and an automatic route selection apparatus sends a packet sent from a communication terminal either to the shortest route or to a bypass route according to the assigned priority level of the communication terminal. More specifically, packets having higher priority levels are sent to the shortest routes with priority, and packets having lower priority levels are sent to bypass routes. As a result, the packets having lower priority levels are automatically bypassed, and the packets having higher priority levels are sent to the shortest routes with priority without being disturbed by the packets having lower priority levels.